javascript 用变量作为object的key

for(let i=0;i<this.props.picData.length;++i){
                    const key=this.props.opList[i]
                    let a =new Object()
                    a[key]=(i+1).toString()
                  //  let dataElem={
                   //     key:(i+1).toString(),
                   // }
                   // dataElem.sss=i
                    console.log("%%%%%%%%%%%",a)
                }